/
dump.go
79 lines (66 loc) · 1.64 KB
/
dump.go
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package main
import (
"fmt"
"github.com/kostya-sh/parquet-go/parquet"
)
var cmdDump = &Command{
Name: "dump",
Help: "dump content of a parquet file",
}
// TODO: support various formats, e.g. CSV, fixed width, pretty print, JSON, etc
var dumpColumn string
var showLevels bool
func init() {
cmdDump.Run = runDump
// TODO: better usage message
cmdDump.Flag.StringVar(&dumpColumn, "c", "", "dump content of the named `column`")
cmdDump.Flag.BoolVar(&showLevels, "levels", false, "dump repetition and definition levels along with the column values")
}
func runDump(cmd *Command, args []string) error {
if len(args) != 1 {
return fmt.Errorf("No files")
}
f, err := parquet.OpenFile(args[0])
if err != nil {
return err
}
defer f.Close()
col, found := f.Schema.ColumnByName(dumpColumn)
if !found {
return fmt.Errorf("no column named '%s' in schema", dumpColumn)
}
const batch = 16
values := make([]interface{}, batch)
dLevels := make([]uint16, batch)
rLevels := make([]uint16, batch)
var n int
for rg, _ := range f.MetaData.RowGroups {
cr, err := f.NewReader(col, rg)
if err != nil {
return err
}
for err != parquet.EndOfChunk {
n, err = cr.Read(values, dLevels, rLevels)
if err != nil && err != parquet.EndOfChunk {
return err
}
for i, vi := 0, 0; i < n; i++ {
d, r := dLevels[i], rLevels[i]
notNull := d == col.MaxD()
if notNull {
fmt.Print(format(values[vi]))
vi++
}
// TODO: consider customizing null value via command lines
if showLevels {
if notNull {
fmt.Printf(" ")
}
fmt.Printf("(D:%d; R:%d)", d, r)
}
fmt.Println()
}
}
}
return nil
}